The present invention has particular application to track rollers, final drives, and other components of track-type machines. The problem of short bearing life in track rollers and final drive assemblies of track-type machines is one that has continuously plagued the industry for some time. Such machines typically operate in environments that are highly destructive to seals and consequently to the underlying bearings.
One approach to this problem is the type seals disclosed in U.S. Pat. No. 3,180,648 which issued Apr. 27, 1965, to Kupfert et al. and U.S. Pat. No. 3,905,607 which issued Sep. 16, 1975, to Roy L. Maguire et al. both of said patents assigned to the assignee hereof. These type metal seals and subsequent improvements have greatly improved track roller bearing life.
These seals, while satisfactory for the normal operation of the average track-type vehicle are found to have some drawbacks when applied to large high speed track vehicles. For example, when the seal diameter gets large, the surface velocity at the seal face increases, increasing heat and centrifugal force problems.
One problem with prior art metal to metal seal assemblies involves damage to the resilient load rings and subsequent reduction in the force applied to the metal seal rings. The resilient load rings are damaged when dirt and abrasives work under the load rings. When this occurs, the abrasives slip by the load rings and into the sealed and lubricated bearing areas. When the force on the metal seal rings is reduced, dirt and abrasives can enter at the seal face.
Other problems of prior art seals is that the arrangement is such that the effects of dirt and grit on the seal face are increased by the normal expansion and contraction of the seal rings in response to heat generation therein by the friction of normal operation. The expansion of the rings at the seal face causes them to separate near the outer diameter, permitting grit to enter the space between the rings and grind away the face of the seal rings.
The present invention is directed to overcoming one or more of the problems as set forth above.